New research from NPD Connected Intelligence shows that Android smartphone users on average download roughly 870 MB of data per month on cellular networks and around 2.5 GB per month on Wi-Fi networks.

The data is noteworthy in light of recent network and pricing strategies by wireless carriers. AT&T Mobility (NYSE:T) and Verizon Wireless (NYSE:VZ) currently charge customers on a per-MB basis, where prices decline as subscribers add more data to their monthly allotment. And Sprint Nextel (NYSE:S) and T-Mobile USA offer unlimited smartphone data services.

NPD's figures, from September, show that smartphone users generally prefer to conduct most of their data communications on Wi-Fi networks--a finding that likely will please wireless carriers that are working to generate revenues from their cellular networks without overloading them. Indeed, most wireless carriers are embarking on various strategies to encourage users to offload more of their communications onto Wi-Fi networks. For example, AT&T operates around 30,000 public Wi-Fi hotspots across the country for just that purpose.

NPD obtained its findings through its SmartMeter software, which is installed on around 1,000 Android smartphones (participants are provided "incentives" to install the software on their phones). NPD said it will soon expand its SmartMeter-powered tracking service to iOS users. The addition of iPhones to NPD's survey could change its findings; prior research has found that iPhone owners generally download more data than Android users.

Interestingly, NPD's cellular vs. Wi-Fi usage statistics are broken down by age. The firm found that 18-24 year olds used the most cellular data of any age group, at 1.05 GB per month. Users aged 55 or older used the least cellular data, just 750 MB per month.

On the Wi-Fi side of things, users between the ages of 25 and 34 downloaded the most data over Wi-Fi, at 3.01 GB per month. Those users 55 and older used the least, at 1.42 GB per month on Wi-Fi.